| Message ID | CAOyqgcX9TQYkLg9vfTJM7OLAPkbu3U-Gon0GJg7K4a5+i7TS7Q@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
Ian Lance Taylor <iant@golang.org> writes: > This patch by Michael Hudson-Doyle rewrites the lfstack code in libgo > to look more like that in the gc library. It also fixes it for arm64. > Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu. > Committed to mainline. This patch broke Solaris/x86 bootstrap: the amd64 lfstack.goc fails to compile: $ /bin/ksh ./libtool --tag=CC --mode=compile /var/gcc/gcc-6.0.0-20150924/12-gcc/./gcc/xgcc -B/var/gcc/gcc-6.0.0-20150924/12-gcc/./gcc/ -B/usr/local/i386-pc-solaris2.12/bin/ -B/usr/local/i386-pc-solaris2.12/lib/ -isystem /usr/local/i386-pc-solaris2.12/include -isystem /usr/local/i386-pc-solaris2.12/sys-include -m64 -DHAVE_CONFIG_H -I. -I/vol/gcc/src/hg/trunk/solaris/libgo -I /vol/gcc/src/hg/trunk/solaris/libgo/runtime -I/vol/gcc/src/hg/trunk/solaris/libgo/../libffi/include -I../libffi/include -pthread -fexceptions -fnon-call-exceptions -fplan9-extensions -Wall -Wextra -Wwrite-strings -Wcast-qual -Werror -minline-all-stringops -D_GNU_SOURCE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I /vol/gcc/src/hg/trunk/solaris/libgo/../libgcc -I /vol/gcc/src/hg/trunk/solaris/libgo/../libbacktrace -I ../../../gcc/include -g -O2 -MT lfstack.lo -MD -MP -MF .deps/lfstack.Tpo -c -o lfstack.lo lfstack.c libtool: compile: /var/gcc/gcc-6.0.0-20150924/12-gcc/./gcc/xgcc -B/var/gcc/gcc-6.0.0-20150924/12-gcc/./gcc/ -B/usr/local/i386-pc-solaris2.12/bin/ -B/usr/local/i386-pc-solaris2.12/lib/ -isystem /usr/local/i386-pc-solaris2.12/include -isystem /usr/local/i386-pc-solaris2.12/sys-include -m64 -DHAVE_CONFIG_H -I. -I/vol/gcc/src/hg/trunk/solaris/libgo -I /vol/gcc/src/hg/trunk/solaris/libgo/runtime -I/vol/gcc/src/hg/trunk/solaris/libgo/../libffi/include -I../libffi/include -pthread -fexceptions -fnon-call-exceptions -fplan9-extensions -Wall -Wextra -Wwrite-strings -Wcast-qual -Werror -minline-all-stringops -D_GNU_SOURCE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I /vol/gcc/src/hg/trunk/solaris/libgo/../libgcc -I /vol/gcc/src/hg/trunk/solaris/libgo/../libbacktrace -I ../../../gcc/include -g -O2 -MT lfstack.lo -MD -MP -MF .deps/lfstack.Tpo -c lfstack.c -fPIC -DPIC -o .libs/lfstack.o /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:32:22: error: redefinition of 'lfPack' /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:16:22: note: previous definition of 'lfPack' was here static inline uint64 lfPack(LFNode *node, uintptr cnt) { ^ /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc: In function 'lfPack': /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:33:38: error: 'PTR_BITS' undeclared (first use in this function) /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:33:38: note: each undeclared identifier is reported only once for each function it appears in /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc: At top level: /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:35:23: error: redefinition of 'lfUnpack' return ((uint64)(node)<<(64-PTR_BITS)) | (cnt&(((1<<CNT_BITS)-1))); ^ /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:19:23: note: previous definition of 'lfUnpack' was here static inline LFNode* lfUnpack(uint64 val) { ^ /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc: In function 'lfUnpack': /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:31:26: error: 'PTR_BITS' undeclared (first use in this function) /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:36:31: note: in expansion of macro 'CNT_BITS' /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc: In function 'lfPack': /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:34:1: error: control reaches end of non-void function [-Werror=return-type] static inline uint64 lfPack(LFNode *node, uintptr cnt) { ^ /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc: In function 'lfUnpack': /vol/gcc/src/hg/trunk/solaris/libgo/runtime/lfstack.goc:37:1: error: control reaches end of non-void function [-Werror=return-type] static inline LFNode* lfUnpack(uint64 val) { ^ cc1: all warnings being treated as errors make: *** [lfstack.lo] Error 1 Rainer
Index: gcc/go/gofrontend/MERGE =================================================================== --- gcc/go/gofrontend/MERGE (revision 227863) +++ gcc/go/gofrontend/MERGE (working copy) @@ -1,4 +1,4 @@ -e069d4417a692c1261df99fe3323277e1a0193d2 +2087b95180caea3477647c449772b7fecc01a71c The first line of this file holds the git revision number of the last merge done from the gofrontend repository. Index: libgo/runtime/lfstack.goc =================================================================== --- libgo/runtime/lfstack.goc (revision 227696) +++ libgo/runtime/lfstack.goc (working copy) @@ -9,25 +9,41 @@ package runtime #include "arch.h" #if __SIZEOF_POINTER__ == 8 -// Amd64 uses 48-bit virtual addresses, 47-th bit is used as kernel/user flag. -// So we use 17msb of pointers as ABA counter. -# define PTR_BITS 47 -#else -# define PTR_BITS 32 -#endif -#define PTR_MASK ((1ull<<PTR_BITS)-1) -#define CNT_MASK (0ull-1) - -#if __SIZEOF_POINTER__ == 8 && (defined(__sparc__) || (defined(__sun__) && defined(__amd64__))) // SPARC64 and Solaris on AMD64 uses all 64 bits of virtual addresses. // Use low-order three bits as ABA counter. // http://docs.oracle.com/cd/E19120-01/open.solaris/816-5138/6mba6ua5p/index.html -#undef PTR_BITS -#undef CNT_MASK -#undef PTR_MASK -#define PTR_BITS 0 -#define CNT_MASK 7 -#define PTR_MASK ((0ull-1)<<3) +# if defined(__sparc__) || (defined(__sun__) && defined(__amd64__)) +static inline uint64 lfPack(LFNode *node, uintptr cnt) { + return ((uint64)(node)) | ((cnt)&7); +} +static inline LFNode* lfUnpack(uint64 val) { + return (LFNode*)(val&~7); +} +# else +# if defined(__aarch64__) +// Depending on the kernel options, pointers on arm64 can have up to 48 significant +// bits (see https://www.kernel.org/doc/Documentation/arm64/memory.txt). +# define PTR_BITS 48 +# else +// Amd64 uses 48-bit virtual addresses, 47-th bit is used as kernel/user flag. +// So we use 17msb of pointers as ABA counter. +# define PTR_BITS 47 +# endif +# endif +# define CNT_BITS (64 - PTR_BITS + 3) +static inline uint64 lfPack(LFNode *node, uintptr cnt) { + return ((uint64)(node)<<(64-PTR_BITS)) | (cnt&(((1<<CNT_BITS)-1))); +} +static inline LFNode* lfUnpack(uint64 val) { + return (LFNode*)((val >> CNT_BITS) << 3); +} +#else +static inline uint64 lfPack(LFNode *node, uintptr cnt) { + return ((uint64)(uintptr)(node)<<32) | cnt; +} +static inline LFNode* lfUnpack(uint64 val) { + return (LFNode*)(uintptr)(val >> 32); +} #endif void @@ -35,16 +51,16 @@ runtime_lfstackpush(uint64 *head, LFNode { uint64 old, new; - if((uintptr)node != ((uintptr)node&PTR_MASK)) { + if(node != lfUnpack(lfPack(node, 0))) { runtime_printf("p=%p\n", node); runtime_throw("runtime_lfstackpush: invalid pointer"); } node->pushcnt++; - new = (uint64)(uintptr)node|(((uint64)node->pushcnt&CNT_MASK)<<PTR_BITS); + new = lfPack(node, node->pushcnt); for(;;) { old = runtime_atomicload64(head); - node->next = (LFNode*)(uintptr)(old&PTR_MASK); + node->next = lfUnpack(old); if(runtime_cas64(head, old, new)) break; } @@ -60,11 +76,11 @@ runtime_lfstackpop(uint64 *head) old = runtime_atomicload64(head); if(old == 0) return nil; - node = (LFNode*)(uintptr)(old&PTR_MASK); + node = lfUnpack(old); node2 = runtime_atomicloadp(&node->next); new = 0; if(node2 != nil) - new = (uint64)(uintptr)node2|(((uint64)node2->pushcnt&CNT_MASK)<<PTR_BITS); + new = lfPack(node2, node2->pushcnt); if(runtime_cas64(head, old, new)) return node; }